Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline and neuronal loss. Understanding the molecular mechanisms underlying AD pathology is crucial for the development of effective therapeutic interventions. In this study, we employed total RNA analysis to investigate gene expression changes in the postcentral gyrus of AD patients, focusing on AffiRNA profiling to elucidate dysregulated pathways.
The postcentral gyrus, a key region involved in sensory processing and integration, is implicated in AD pathology. Accumulating evidence suggests that dysregulation of gene expression in this brain region contributes to the progression of AD. Total RNA analysis provides a comprehensive view of transcriptomic alterations associated with AD, facilitating the identification of potential therapeutic targets.
Materials and Methods
Postmortem brain tissue samples were obtained from the postcentral gyrus of clinically diagnosed Alzheimer's disease patients and age-matched controls. Tissue samples were carefully dissected and processed for total RNA extraction using TRIzol reagent (Thermo Fisher Scientific) according to the manufacturer's instructions. RNA quality and quantity were assessed using spectrophotometry and gel electrophoresis.
AffiRNA profiling was performed to analyze gene expression levels in the postcentral gyrus samples. AffiRNA technology utilizes a highly sensitive and specific microarray platform to simultaneously quantify thousands of RNA transcripts. Briefly, total RNA samples were reverse transcribed into cDNA and labeled with fluorescent dyes. Labeled cDNA samples were hybridized to AffiRNA microarrays, followed by washing and scanning using a microarray scanner.
Differential gene expression analysis was conducted using established bioinformatics tools and pipelines. Raw microarray data were processed, normalized, and filtered to remove low-quality probes. Statistical analysis was performed to identify genes that were differentially expressed between AD patients and controls, with significance thresholds adjusted for multiple testing. Pathway enrichment analysis was then performed to identify overrepresented biological pathways among the dysregulated genes.
Results
Total RNA analysis revealed widespread dysregulation of gene expression in the postcentral gyrus of Alzheimer's disease patients. A large number of genes were found to be significantly upregulated or downregulated in AD brains compared to controls. Among the dysregulated genes were those involved in neuronal function, including neurotransmitter receptors, ion channels, and synaptic proteins.
Pathway analysis identified several key biological processes that were perturbed in AD brains. Notably, pathways related to amyloid processing and tau phosphorylation, two hallmarks of AD pathology, were significantly enriched among the dysregulated genes. Additionally, genes involved in neuroinflammation and immune response were found to be dysregulated, highlighting the role of neuroinflammation in AD pathogenesis.
Discussion
The findings of this study provide valuable insights into the molecular mechanisms underlying Alzheimer's disease pathology in the postcentral gyrus. Dysregulation of genes involved in neuronal function and synaptic plasticity suggests disruptions in synaptic transmission and connectivity, which are known to occur early in the course of AD.
The enrichment of pathways related to amyloid processing and tau phosphorylation is consistent with the accumulation of amyloid-beta plaques and neurofibrillary tangles observed in AD brains. Aberrant regulation of these pathways likely contributes to neuronal dysfunction and cell death in AD.
Furthermore, the dysregulation of genes involved in neuroinflammation and immune response suggests a role for neuroinflammation in AD pathogenesis. Activation of microglia and astrocytes, as well as infiltration of peripheral immune cells, may exacerbate neurodegeneration and contribute to disease progression.
In conclusion, total RNA analysis of the postcentral gyrus in Alzheimer's disease patients reveals widespread dysregulation of gene expression, implicating multiple molecular pathways in disease pathogenesis. These findings provide a foundation for further investigation into the mechanisms underlying AD and may lead to the identification of novel therapeutic targets for this devastating neurodegenerative disorder.